Wow. I still have this link.
http://www.sfu.ca/~cth/ltmodem/doc/Ltmodem.html
Yeah - you need the kernel source (
http://www.kernel.org/ ) - if DSL doesn't have a way to get DSL-specific stuff and then need to compile the drivers. I *highly* recommend buying a cheap external hardware modem (or even DSL - net connection, not Damn Small Linux - if possible). Some people may have easy installs and flawless operation. I had *huge* headaches and when I finally got them 'working' it crashed my box as often as it connected to the net. However, until my cheap used hardware modem died *g*, it worked great.